As filed with the Securities and Exchange Commission on March 28, 2019

Registration No. 333-                

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

STERIS plc

(Exact name of registrant as specified in its charter)

STERIS plc 2006 Long-Term Equity Incentive Plan (As Assumed, Amended and Restated Effective March 28, 2019)

(Full title of the plan)

J. Adam Zangerle

STERIS plc

70 Sir John Rogerson’s Quay

Dublin 2 Ireland

(Name and address of agent for service)

+353 1 232 2000

(Telephone number, including area code, of agent for service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

PART I

INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

The information specified in Item 1 and Item 2 of Part I of the Registration Statement is omitted from this filing in accordance with the provisions of Rule 428 under the Securities Act and the introductory note to Part I of Form S-8. The documents containing the information specified in Part I will be delivered to the holders as required by Rule 428(b)(1).

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

The following documents filed with the Securities and Exchange Commission (the “Commission”) by the Registrant and STERIS UK are hereby incorporated in this Registration Statement by reference:

STERIS UK adopted Accounting Standards Update 2017-07 “Compensation – Retirement Benefits – Improving the Presentation of Net Periodic Pension and Net Periodic Postretirement Benefit Cost” on April 1, 2018, which resulted in a retrospective reclassification of certain components of benefit costs that does not impact Net Income as previously reported as presented in the Consolidated Statements of Income in STERIS UK’s Annual Report on Form 10-K for the year ended March 31, 2018. STERIS UK’s Quarterly Reports on Form 10-Q for the quarters ended June 30, 2018, September 30, 2018 and December 31, 2018 reflect this change. STERIS UK has not recast its financial statements or related disclosures appearing in its Annual Report on Form 10-K for the year ended March 31, 2018 to reflect these changes because the impact on the information previously presented is not material.

In addition, all documents filed by the Registrant pursuant to Section 13(a), 13(c), 14, and 15(d) of the Exchange Act, subsequent to the date of this Registration Statement (other than any such documents or portions thereof that are furnished under Item 2.02 or Item 7.01 of a Current Report on Form 8-K, unless otherwise indicated therein, including any exhibits included with such Items), and prior to the filing of a post-effective amendment to this Registration Statement that indicates that all securities offered have been sold or that deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of filing of such documents.

Any statement contained in this Registration Statement or in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration

Statement to the extent that a statement contained or incorporated by reference herein or in any subsequently filed document that is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Item 4. Description of Securities.

Not applicable.

Item 5. Interests of Named Experts and Counsel.

Not applicable.

Item 6. Indemnification of Directors and Officers.

The Registrant is currently a public limited company incorporated under the laws of Ireland.

Subject to exceptions, Irish law does not permit a company to exempt a director or certain officers from, or indemnify a director against, liability in connection with any negligence, default, breach of duty or breach of trust by a director in relation to the company. The exceptions allow a company to:

The memorandum and articles of association of the Registrant includes a provision which entitles every director to be indemnified by the Registrant to the fullest extent permitted by law (including by funding any expenditure incurred or to be incurred by him or her) against any loss or liability incurred in his or her capacity as a director. The memorandum and articles of association of the Registrant also states that where a person is so indemnified, such indemnity may extend to all costs, losses, expenses and liabilities incurred by him or her. Any funds provided to a director to meet any expenditure incurred by him in connection with defending himself or in an investigation of any negligence, default, breach of duty or breach of trust by him or otherwise, must be repaid if he or she is convicted or judgment is given against him. In proceedings where negligence, default, breach of duty or breach of trust against a director has or may be established (or in anticipation of any such proceedings), an Irish court has the power to grant a director or other officer relief from liability on the grounds that he or she acted honestly and reasonably and that, having regard to all the circumstances of the case, he or she ought fairly to be excused of the wrong concerned.

The memorandum and articles of association of the Registrant also provides the Registrant’s board of directors with authority to purchase and maintain insurance at the expense of the Registrant for the benefit of any person who is, or was at any time, a director or other officer or employee of the company or any associated company.

In addition to the provisions of the memorandum and articles of association of the Registrant, it is common for a public limited company to enter into separate deeds of indemnity with directors or officers which essentially indemnifies the director or officer against claims brought by third parties to the fullest extent permitted under Irish law. The Registrant intends to enter into such deeds of indemnity with each of its directors and officers.

Item 7. Exemption from Registration Claimed.

Not applicable.

Item 8. Exhibits.

Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) of this Item 9 do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference herein.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Mentor, State of Ohio, on this 28th day of March, 2019.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities indicated on March 28, 2019.

Exhibit 5.1

STERIS plc

70 Sir John Rogerson’s Quay

Dublin 2

Ireland

D02 R296

Dear Sirs

Registration Statement on Form S-8 of STERIS plc

We are acting as Irish counsel to STERIS plc, a public limited company incorporated under the laws of Ireland (company number 595593) (the “Company”), in connection with the filing by the Company, on the date hereof, of a registration statement on Form S-8 pursuant to the U.S. Securities Act of 1933, as amended (the “Securities Act”) (the “Registration Statement”), to which this Opinion is an exhibit, with the U.S. Securities and Exchange Commission (the “Commission”), pursuant to which the Company will register, under the Securities Act, ordinary shares in the capital of the Company (“Ordinary Shares”) that may become issuable pursuant to the STERIS plc 2006 Long-Term Equity Incentive Plan (As Assumed, Amended and Restated Effective March 28, 2019) (the “Plan”).

In connection with this Opinion, we have reviewed:

Based on the foregoing, and subject to the further assumptions, qualifications and limitations set out in this Opinion, we are of the opinion that the Ordinary Shares, when issued pursuant to the terms of the

Plan (including any applicable and duly authorised award agreement under the Plan), subject to receipt by the Company of the full consideration payable therefor, will be validly issued, fully paid and non-assessable (“non-assessable” is a phrase which has no defined meaning under Irish law, but, for the purposes of this Opinion, shall mean the registered holders of such Ordinary Shares are not subject to calls for additional payments on such shares).

For the purposes of this Opinion, we have assumed: (i) the truth and accuracy of the contents of all documents and searches reviewed as to factual matters, but have made no independent investigation regarding such factual matters; (ii) all signatures, initials, seals and stamps contained in, or on, all documents submitted to us are genuine; (iii) all documents submitted to us as originals are authentic and complete and that all documents submitted to us as copies (including without limitation any document submitted to us as a pdf (or any other format) attachment to an email) are complete and conform to the originals of such documents, and the originals of such documents are authentic and complete; (iv) at the time of the allotment and issue of any Ordinary Shares pursuant to the terms of the Plan, the Company will have a sufficient number of authorised but unissued Ordinary Shares in its share capital (being at least equal to the number of Ordinary Shares to be allotted and issued); (v) at the time of the allotment and issue of any Ordinary Shares (or the grant of any right to subscribe for, or convert any security into, Ordinary Shares (a “convertible right”)) pursuant to the terms of the Plan, to the extent required, (A) the directors of the Company will, in accordance with section 1021 of the Companies Act 2014 of Ireland (the “Companies Act”), have been generally and unconditionally authorised by the shareholders of the Company to allot a sufficient number of “relevant securities” (within the meaning of that section) (being at least equal to the number of Ordinary Shares the subject of such allotment and issuance or grant of a convertible right) and (B) the directors of the Company will, in accordance with section 1023 of the Companies Act, have been empowered by the shareholders of the Company to allot and issue such Ordinary Shares or grant convertible rights as if the section 1022(1) did not apply to such allotment and issuance or grant; (vi) the full consideration for all Ordinary Shares to be allotted and issued pursuant to the Plan will have been received by the Company prior to the issuance of such Ordinary Shares; (vii) no Ordinary Shares will be allotted and issued pursuant to the Plan for less than their nominal value; (viii) no Ordinary Shares will be allotted and issued pursuant to the Plan for consideration other than cash; (ix) no Ordinary Shares will be allotted and issued other than pursuant to a resolution of the board of directors of the Company or a duly authorised committee thereof; and (x) the Company shall not give an financial assistance, as contemplated by sections 82 and 1043 of the Companies Act for the purpose of any acquisition of any Ordinary Shares pursuant to the Plan, save as permitted by, or pursuant to an exemption to, the said sections 82 and 1043.

This Opinion is based upon, and limited to, the laws of Ireland as is in effect on the date hereof and is based on legislation published and cases fully reported before that date and our knowledge of the facts relevant to the opinions contained herein. We have assumed without enquiry that there is nothing in the laws of any jurisdiction other than Ireland which would, or might, affect our opinion as stated herein. We have made no investigations of, and we express no opinion on, the laws of any jurisdiction other than Ireland or the effect thereof. This Opinion is expressed as of the date hereof and we assume no obligation to update this Opinion.

This Opinion is furnished to you and the persons entitled to rely upon it pursuant to the applicable provisions of the Securities Act strictly for use in connection with the Registration Statement and may not be relied upon by any other person without our prior written consent. This Opinion is confined strictly to the matters expressly stated herein and is not be read as extending by implication or otherwise to any other matter.

2

We hereby consent to the filing of this Opinion as Exhibit 5.1 to the Registration Statement and to the reference to Matheson therein. In giving such consent, we do not admit that we are included in the category of persons whose consent is required under section 7 of the Securities Act, or the rules and regulations of the Commission promulgated thereunder.

This Opinion and the opinions given in it are governed by, and construed in accordance with, the laws of Ireland.

Yours faithfully

/s/ Matheson

MATHESON

3

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8) of STERIS plc, a public limited company organized under the laws of Ireland, pertaining to the STERIS plc 2006 Long-Term Equity Incentive Plan, (As Assumed, Amended and Restated Effective March 28, 2019) of our reports dated May 30, 2018, with respect to the consolidated financial statements and financial statement schedule of STERIS plc, a public limited company organized under the laws of England and Wales (“STERIS UK”), and the effectiveness of internal control over financial reporting of STERIS UK (excluding the internal control over financial reporting of entities that were acquired during fiscal 2018) included in its Annual Report (Form 10-K) for the year ended March 31, 2018, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Cleveland, Ohio

March 27, 2019

Exhibit 23.2

LETTER REGARDING UNAUDITED INTERIM FINANCIAL INFORMATION

Shareholders and Board of Directors

STERIS plc

We are aware of the incorporation by reference in the Registration Statement (Form S-8) of STERIS plc, a public limited company organized under the laws of Ireland, for the registration of 7,288,972 of its ordinary shares of our reports dated August 8, 2018, November 6, 2018, and February 11, 2019 relating to the unaudited consolidated interim financial statements of STERIS plc, a public limited company organized under the laws of England and Wales, that are included in its Forms 10-Q for the quarters ended June 30, 2018, September 30, 2018, and December 31, 2018.

/s/ Ernst & Young LLP

Cleveland, Ohio

March 27, 2019